Metabolism of [11
C](R)-PK11195. (A) Radiochromatogram from gradient HPLC analysis of human plasma after i.v. injection of [11C](R)-PK11195 (peak III). Peaks I and II represent labelled metabolites that are more polar than unchanged [11C](R)-PK11195. (B) Time course for the fraction (%) of radioactivity in plasma that represents unchanged [11C](R)-PK11195 and its metabolites in six healthy human subjects (mean, SD).